1. Field
The invention relates to a vehicle brake hydraulic pressure control apparatus that can execute a pressurizing control by driving a motor.
2. Related Art
In a vehicle brake hydraulic pressure control apparatus that can execute a pressurizing control by driving a motor, a rotation state of the motor is detected to control the revolution speed of the motor and/or to detect a malfunction of the motor. It is possible to determine the rotation state of the motor based on a counter electromotive force of the motor which is obtained by detecting a terminal voltage of the motor.
It is desirable to detect a terminal voltage of the motor at a moment at which no electric current flows to the motor (no voltage is applied to the motor) in order to acquire an accurate counter electromotive force of the motor. Therefore, JP 2001-10471 A describes that in a PWM (Pulse Width Modulation) control in which an electric current to a motor is on and off repeatedly based on a duty ratio, the terminal voltage of the motor is measured within an off period during which no voltage is applied to the motor.